1. Field of the Invention
The present invention relates to an electronic throttle device and a method of manufacturing the same. More specifically, the present invention relates to a connection structure of the electronic throttle device.
2. Description of the Related Art
Conventionally, a vehicular engine includes an electronic throttle device having a throttle valve and a motor. An angle (i.e., opening degree) of the throttle valve is controlled by driving the motor in accordance with a pressing amount of an accelerator pedal pressed by a driver. The electronic throttle device includes a throttle body having a throttle bore part. The throttle bore part has an approximately cylindrical shape and has an inlet portion at one end thereof. An upstream air hose is located at an outside of the inlet portion of the throttle bore part, and is fastened to the inlet portion with a fastening member (e.g., a hose band) from an outside of the upstream air hose. The inlet portion of the throttle bore part has a bulge at its outer circumference, for improving a connecting force of a connecting part between the throttle bore part and the upstream air hose, and thereby an airtightness of the connecting part is improved and an air leakage is reduced. The electronic throttle device further includes a housing base for housing the motor therein, and the housing base is attached to the throttle body through the throttle bore part and a concave portion.
The throttle body is generally formed by die-casting with a two-cavity mold for improving a productivity. When the electronic throttle device is used for an engine having a turbocharger or a supercharger, the throttle bore part may receive a high positive pressure. Thus, when a part of the bulge is lacked, the connecting force between the throttle bore part and the upstream air hose may be insufficient to prevent an air leakage from the connecting part. Thereby, an accuracy of an intake-air control may be reduced, and an output and a fuel consumption of the vehicular engine also may be reduced.
JP-2002-295756A discloses a swivel-hose joint for being connected with a hose. The swivel-hose joint includes a joint body, a pipe body having one end connected with the hose and the other end inserted into the joint body, and a C-ring. The C-ring is disposed between the joint body and the pipe body, so that the pipe body is not pulled out from the joint body and the pipe body can smoothly rotate with respect to the joint body. This joint structure is designed so that the hose does not twist when the swivel-hose joint rotates. However, this joint structure is not designed for improving an airtightness and a connecting force between the swivel-hose joint and the hose, and/or preventing the hose from being pulled out from the swivel-hose joint.